Balloon catheter assembly

ABSTRACT

A balloon catheter assembly including a balloon and a catheter. The catheter has a chuck and a multi-tube unit including at least an inner tube and an outer tube arranged slidably and coaxially with the inner tube. The balloon is removably fixed to the distal portion of the inner tube by the chuck which is pulled into the outer tube to be closed, and which is extended from the outer tube to be opened. The catheter is introduced to a required dwelling portion in a blood vessel by a tubular guide sheath having an inner diameter such that the guide sheath admits the catheter, and the expanded balloon is left in the dwelling portion to occlude the blood vessel.

BACKGROUND OF THE INVENTION

This invention relates to a balloon catheter assembly comprising adetachable occluding balloon for occluding a path of a body fluid suchas a blood vessel, and to a guide sheath for guiding the introduction ofthe catheter.

An occluding balloon is used for mainly occluding a blood vessel such asan artery when, for example, a percutaneous surgery of congenitalcardiopathy due to patent duct arteriosus is carried out.

The PCT Patent Publication Sho 57-500720, for example, discloses aballoon catheter having an occluding balloon in which the balloon isseparable at a required portion. However, this balloon catheter has thefollowing problems:

Since the balloon has a complicated structure, it cannot be renderedsmall.

Further after the balloon has been expanded by accident, it cannot becontracted again.

Still further, it is feared that since the balloon is fitted only to thedistal portion of the catheter, it may fall off by accident during itsoperation.

A similar balloon catheter is disclosed in the Japanese unexaminedpatent application publication Sho 59-34269. Since the balloon is alsoonly fitted to a cannula, it may fall off by accident. If the connectingstrength of the fitting portion is enhanced, the balloon can beprevented from falling off. However, it becomes difficult to separatethe balloon from the catheter; the balloon gives an excess stress to theblood vessel to be occluded; and such a bulky structure of the balloonmay cause the breakage thereof.

The balloon can be threadably connected to the catheter by means ofscrew. When the balloon is to be separated from the distal portion ofthe catheter assembly, however, the torque is not easily transmitted tothe connecting portion of the balloon with the result that this maycause such trouble that the balloon would not be easily separated fromthe catheter, and the balloon would be twisted to be broken as well.

As a method of introducing an occluding balloon to a dwelling portion ofblood vessel, such as a peripheral blood vessel e.g. a cerebral bloodvessel, the balloon is slightly expanded in advance to be carried by ablood stream. However, this method is not suitable for sending anoccluding balloon to a vascular portion where a blood flow is ratherweak. This method is not applicable to the transmission of the balloonto the vicinity of a heart.

The method of transmitting an occluding balloon in a blood vessel whileexposing the balloon as disclosed in the PCT Patent Publication Sho57-500720, will not only lead to the breakage of the balloon but makesit difficult to easily and accurately transmit the balloon to therequired dwelling portion.

This invention provides a balloon catheter assembly in which a balloondoes not easily fall off during the transmitting operation therebyensuring the introduction of the balloon to the required portion to beoccluded, and, even if the balloon is expanded by accident, it can becontracted to the original size if a filler has not yet been gelled.

This invention further provides a balloon catheter assembly in which anoperator can easily observe how a balloon occludes the required portion.

The invention still further provides a balloon catheter which is simplein structure and in which a balloon can be rendered small and can not beeasily broken.

SUMMARY OF THE INVENTION

This invention is fundamentally characterized by comprising anexpandable balloon having an opening at a proximal portion thereof, aninner tube having a distal portion detachably fitted in the opening ofthe balloon, a chuck surrounding a distal portion of the inner tube andfixed to an outer peripheral surface the inner tube, the chuck having aplurality of holding pieces whose distal ends extend outwardly andradially, and an outer tube coaxially surrounding the inner tube leavinga space therebetween, wherein the holding portions are adapted to bepressed inwardly by a distal end of the outer tube to hold the proximalportion of the balloon when the inner tube is pulled into the outertube, and the holding portions are automatically opened and expanded torelease the proximal portion of the balloon when the chuck is pushed outof the distal end of the outer tube.

With the catheter assembly having the fundamental structure as describedabove, a check valve may be provided at the proximal end of the outertube such that the inner tube is extended out through the check valvethereby preventing a body fluid such as blood from flowing reverselywhen the distal portion of the catheter is inserted into a body.

Further, an infusion port may be connected to the check valve providedat the outer tube, and another infusion port for a balloon expandingfiller may be connected to the proximal end of the outer tube.

Still further, the unexpanded balloon may be properly accommodated inthe distal portion of the outer tube.

This invention is characterized by having a further fundamentalstructure comprising an expandable balloon having an opening at aproximal portion thereof, an inner tube having a distal portiondetachably inserted in the opening of the balloon, an intermediate tubecoaxially surrounding the inner tube leaving a space therebetween andprovided at a distal portion thereof with a chuck having a plurality ofopenable holding pieces, and an outer tube coaxially surrounding theintermediate tube leaving a space therebetween, wherein the chuck ispulled in the outer tube, and the chuck releases the proximal portion ofthe balloon when the chuck is pushed out of the distal end of the outertube.

With the catheter assembly having the second fundamental structure, theintermediate and outer tubes may have connectors connected to respectivecheck valves provided at the proximal ends of the intermediate and outertubes such that the intermediate tube is extended outwardly through thecheck valve of the outer tube and the inner tube is extended outwardlythrough the check valve of the intermediate tube thereby preventing abody fluid such as blood from flowing reversely.

Further, infusion ports may be connected to the check valves at theinner and outer tubes, and another infusion port for a balloon expandingfiller may be connected to the proximal end of the inner tube.

Still further, the unexpanded balloon may be suitably installed in thedistal end of the outer tube.

More further, a circular thick portion is formed at the middle circularportion of the balloon such that the balloon takes a bottle-gourd shapewhen it is expanded.

This invention further provides a balloon catheter assembly whichcomprises a balloon catheter in which a balloon communicates with thedistal end of a multi-tube unit comprising an inner tube and an outertube slidably and coaxially mounted thereon, and a chuck whichselectively opens and closes at the distal end of the outer tubeselectively to hold and release the balloon, a guide sheath which has atube body having such an inner diameter that the guide sheath permitsthe balloon catheter to be guided and which guides the balloon to arequired dwelling portion, and a guide sheath which guides the balloonto a required dwelling portion.

It is preferred that a check valve be connected to the proximal end ofthe guide sheath and an infusion port in series.

It is also preferred that the guide sheath is made of material mixedwith X-ray opaque substance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an enlarged cross-sectional view of the distal portion of aoccluding balloon catheter according to this invention;

FIG. 2 is a perspective view of an intermediate tube of the catheter inFIG. 1;

FIG. 3 is a cross-sectional view of the same embodiment as that in FIG.1, with the balloon expanded;

FIG. 4 is a plan view of an embodiment of the overall occluding ballooncatheter assembly according to this invention;

FIG. 5 is a plan view of an embodiment of the guide sheath;

FIGS. 6 and 7 are cross-sectional views of other embodiments of theoccluding balloon catheter assembly according to this invention;

FIG. 8 is a perspective view of the inner tube of the catheter in FIG.7;

FIG. 9 is a cross-sectional view of the same embodiment as that in FIG.7, with the balloon expanded;

FIG. 10 is a cross-sectional view of another embodiment of the occludingballoon catheter; and

FIGS. 11 to 13 are cross-sectional views of modifications of theballoon.

DETAILED DESCRIPTION

This invention will be explained with reference to embodiments shown inthe drawings.

FIG. 1 shows the distal portion of the occluding balloon catheteraccording to this invention. As seen from this figure, a main catheter 1is formed with a triple-tube unit comprising an outer tube 2, anintermediate tube 3 and an inner tube 4 arranged coaxially with eachother. The inner tube 4 has a slightly thinner distal portion 4a and isinserted in an opening 5b formed in the center of the proximal portion5a of a balloon 5 so as to communicate with the interior of the balloon5.

The intermediate tube 3 surrounding the inner tube 4 at a spacing isformed at its distal end with a chuck portion 6 having a plurality ofholding portions 6a which selectively opens and closes. As shown in FIG.2, the holding portions 6a forming the chuck portion 6 are four innumber and are integral with the intermediate tube 3. They normally openmost widely at their distal ends, and the inner diameter defined bytheir distal ends is much larger than the outer diameter of the proximalportion 5a of the balloon when they are opened. On the distal end ofeach of the holding portions 6a is formed a hook 6b projecting inwardlyof the chuck 6. The hooks 6b bite into the outer peripheral wall of theproximal portion 5a of the balloon 5 to hold the same, at the time ofengagement as shown in FIG. 1.

The outer tube 2 surrounding the intermediate pipe at a spacing from theouter periphery of the outer tube 2 has at its distal end an innerdiameter much smaller than the diameter defined by the distal end of thechuck 6 formed on the intermediate tube 3 when the chuck is expandedsuch that the movement of the intermediate tube 3 into and out of theouter tube 2 causes the chuck 6 to be pushed inwardly by theintermediate tube 3 and to be released therefrom, respectively, wherebythe chuck 6 freely closes or opens.

When a filler is introduced into the balloon 5 through the inner tube 4,the balloon 5 is expanded as shown in FIG. 3. The material of theballoon 5 may be mixed with X-ray opaque substance such as platinum,gold or the like which constitutes a marker.

The total structure of this occluding catheter assembly will beexplained.

As shown in FIG. 4, the proximal ends of the intermediate tube 3 and theouter tube 2 are connected to check valves 8a and 8b, respectively, viaconnectors 7a and 7b. However, the connectors 7a and 7b are not alwaysnecessary, but the proximal ends of the intermediate tube 3 and theouter tube 2 may be directly connected to the respective check valves 8aand 8b. Further, the intermediate tube 3 is led out from the outer tube2 through the check valve 8b connected to the outer tube 2, and likewisethe inner tube 4 is led out from the intermediate tube 3 through thecheck valve 8a connected to the intermediate tube 3, thereby preventinga body fluid such as blood from flowing reversely.

As shown in FIG. 4, the check valves 8a and 8b are connected to infusionports 10a and 10b comprising two-way valves, three way valves or thelike, respectively, via connecting tubes 9a and 9b. Physiological saltsolution, for example, is infused continuously of intermittently in thetubes 3 and 4 through the infusion ports 10a and 10b, so that blood orother body fluid which would otherwise enter the outer tube 2 and theintermediate tube 3 during the operation of the catheter, is excluded.This process is intended to prevent blood or the like entering thecatheter from being coagulated so as to operate the catheter normally.

An infusion port 10c (preferably, a two-way valve or a three-way valve)is connected to the proximal end of the inner tube 4 via a connector 7cso as to infuse a balloon expanding filler.

In general, the inner tube 4, the intermediate tube 3 and the outer tube2 are made of such thermoplastic resin as polyethylene, polyolefin,ethylene-vinylacetate copolymer, polyester, polyvinylchloride,polyurethane, fluoric resin and nylon.

The material of the balloon 5 can be selected form elastic material suchas silicone rubber, polyurethane and latex. A mesh made of nylon,polyethelene terephthalate, polyurethane or the like is embedded in thethick portion of the balloon 5 such that the balloon 5 is not expandedbeyond a required size.

A guide sheath 11 comprises a tube body having an inner diameterpermitting the catheter 1 as well as the balloon 5 to be inserted intothe sheath 11. As shown in FIG. 5, a connector 12 accommodating a checkvalve is preferably connected to the proximal end of the guide sheath11. An infusion port 13 for infusing physiological salt solution intothe guide sheath 11 connected to the connector 12 via a tube 14. Thisarrangement hinders the reverse flow of blood or the like when the guidesheath 11 is inserted in the body and excludes the blood or the likewhich has entered the guide sheath 11 by means of physiological saltsolution or the like.

Like the catheter 1, the guide sheath 11 is generally made ofthermoplastic resin such as polyolefin, ethylene-vinylacetate copolymer,polyester, polyvinylchloride, polyurethane, fluoric resin or nylon.

There will be explained the process how to dwell the balloon in a bloodvessel by using the balloon catheter assembly.

First, a guide wire (not shown) is moved to a balloon dwelling portionby the similar method of angiography. The guide wire may be furtheradvanced beyond the dwelling portion. Secondly, the guide sheath 11 setwith a dilator (not shown) is inserted into the blood vessel along theguide wire until it reaches the balloon dwelling portion. The dilator isrequired when the guide sheath 11 begins to be inserted into the bloodvessel, but it may be removed when the guide sheath 11 is moved to theballoon dwelling portion. Thirdly, the guide wire is removed when theguide sheath 11 has been moved to the balloon dwelling portion.

Thereafter, the catheter 1 is introduced to the dwelling portion throughthe guide sheath 11 with the balloon 5 held at the distal end of thecatheter 1 as shown in FIG. 1. During the introduction of the catheter1, the balloon 5 does not fall off because its distal portion 5a isfirmly held by the chuck 6 formed on the distal end of the intermediatetube 3.

After the balloon 5 has been positioned in the dwelling portion asdescribed above, the balloon expanding filler is introduced in theballoon 5 through the infusion port 10c at the proximal end of the innertube 4 to expand the balloon 5 to a required size as shown in FIG. 3.The filler is made of gelable liquid such silicone RTV (Silicone RubberKE12 RTV --a trade name of Shin-etsu Kagaku Kogyo Kabushiki Kaisha),cross-linked type modified polyvinyl alcohol or the like (with whichX-ray opaque substance such as tungsten, bismuth oxide, barium sulfateor the like may be mixed). When the filler is mixed with the X-rayopaque substance, the catheter assembly can be used in X-rayfluoroscopy.

After the filler has been cured in the balloon 5, the outer tube 2 isretracted towards the proximal ends of the intermediate tube 3 and theinner tube 4, whereby the check 6 opens automatically and is disengagedfrom the proximal portion 5a of the balloon 5. Then, the distal end ofthe inner tube 4 is released from the proximal portion 5a of the balloon5 by pulling the inner tube 4 towards it proximal end with the balloon 5left in the required dwelling portion. If necessary, physiological saltsolution is continuously or intermittently infused into the catheterthrough the infusion ports 10a and 10b.

In the above embodiment, the outer tube 2 has the same diameter over itsentire length. As shown in FIG. 6, however, the distal portion 2a may beexpanded to have such a large inner diameter that the portion 2a admitsthe unexpanded balloon 5 with the proximal portion 5a of the balloon 5held by the chuck 6 formed on the intermediate tube 3. This structure ispreferably used to hinder the balloon 5 from being damaged while theballoon 5 is being moved to the dwelling portion.

In FIG. 7 is shown another embodiment of the distal portion of theoccluding balloon catheter according to this invention. As clearlyunderstood from this figure, a catheter 21 has a double-tube unitcomprising an outer tube 22 and an inner tube 23 coaxial therewith. Thedistal portion 23a of the inner tube 23 is formed slightly thinner thanits remaining part and is inserted in an central opening 24b formed inthe center of the proximal portion 24a of a balloon 24 so as tocommunicate with its interior.

On the distal end of the inner tube 23 is formed a chuck 25 comprisingthree holding pieces 25a arranged equidistantly in the circumferentialdirection so as to surround the distal portion 23a of the inner tube 23.As shown in FIG. 8, the holding portions 25a or normally opened mostwidely at their distal ends in such a manner that they can hold theouter peripheral surface of the proximal portion 24a of the balloon 24.

The distal end of each of the holding pieces 25a is formed with aninwardly projecting hook 25b. The hooks 25b bite in the outer peripheralsurface of the proximal portion 24a of the balloon 24 to hold the samewhen the balloon 24 is connected to the catheter 21 as shown in FIG. 7.

The distal portion of the outer tube 22, which surrounds the inner tube23 at a spacing from its outer peripheral surface, has an inner diametermuch smaller than the diameter of the distal end of the chuck 25 formedon the inner tube 23 when the chuck 25 is opened. The movement of theinner tube 23 into and out of the outer tube 22 causes the chuck 25 tobe pushed inwardly by the outer tube 22 and released therefrom,respectively, whereby the chuck 25 freely closes or opens.

The structure, functions and usage of this embodiment other than thoseas described above are the same as those of the embodiment shown inFIG. 1. As shown in FIG. 9, after the balloon 24 has been expanded to arequired size, the outer tube 22 is moved towards the proximal end ofthe inner tube 23 to open the chuck 25a, and then the inner tube 23 isalso pulled towards it proximal end, whereby the distal portion 23a ofthe inner tube 23 is released from the proximal portion 24 of theballoon 24 with only the balloon 24 left in the required dwellingportion.

This embodiment can be modified as shown in FIG. 10, in which the distalportion 22a may be expanded to have such a large diameter than theportion 22a admits the unexpanded balloon 24 with the proximal portion24a of the balloon 24 held by the chuck 25 formed on the inner tube 22.This structure is preferably used to hinder the balloon 24 from beingdamaged while the balloon 24 is being moved to the dwelling portion.

The shape of the balloon is not limited to that of the balloon 24 of thesecond embodiment, but, as shown in FIG. 11, the distal portion 24c ofthe balloon 24 may be made solid, and a belt-type marker 24d made ofX-ray opaque substance as described above may be fixed to or embedded inthe outer peripheral surface of the portion 24c. Further, as shown inFIG. 12, the intermediate portion of the part, to be expanded, of theballoon 24 may be formed with a thick portion 24e so as to take abottle-gourd shape when the balloon 24 is expanded as shown in FIG. 13.It is preferred that the opening 24b of the balloon 24 should be closedexcept when the inner tube is inserted in a blood vessel or the likesuch that the filler in the balloon is prevented from being dischargedfrom the opening 24b.

The balloon catheter assembly according to this invention has such astructure that the catheter comprises a double-tube unit or atriple-tube unit in which the inner tube or the outer tube of thestructures is provided at the distal end thereof with a freely openableand closable chuck thereby to hold or release the balloon. Therefore,the catheter assembly according to this invention provides the followingtechnical features:

The balloon does not fall out during the operation of the catheterassembly and it becomes easy to collect the balloon again.

Further, when the balloon is expanded by accident, it can be contractedif the filler has not yet been gelled therein.

Still further, the breakage of the balloon can be prevented byinstalling the balloon in the outer tube.

In addition, the simple structure of the balloon enables the wholecatheter assembly to be small-sized.

INDUSTRIAL APPLICABILITY

The balloon catheter assembly according to this invention is useful toocclude a blood vessel such as a patient's artery during percutaneoussurgery.

We claim:
 1. A balloon catheter assembly, comprising:an expandableballoon having an opening in a proximal end portion thereof andincluding a marker made of an X-ray opaque substance; an inner tubehaving a distal end portion which is removably inserted in said openingof said balloon; an intermediate tube coaxially surrounding said innertube with a space therebetween; a chuck at a distal end of saidintermediate tube, said chuck comprising a plurality of expandable andcontractible holding portions; and an outer tube surrounding saidintermediate tube with a space therebetween; said chuck being closedwhen pulled into said outer tube and pressed by said distal end of saidouter tube to thereby hold said proximal end portion of said balloon,and said chuck being opened when pushed out of said distal end of saidouter tube, to thereby release said proximal end portion of saidballoon.
 2. The balloon catheter assembly according to claim 1,wherein:said intermediate tube and said outer tube have proximal endsconnected to respective check valves; said intermediate tube extendsoutward from said outer tube via said check valve connected to saidouter tube; and said inner tube extends outward from said intermediatetube via said check valve connected to said intermediate tube, such thata body fluid is prevented from flowing reversely when said distalportion of said catheter is inserted in a body.
 3. The balloon catheterassembly according to claim 2, further comprising infusion portsconnected to said check valves which are connected to said intermediatetube and said outer tube, respectively.
 4. The balloon catheter assemblyaccording to claim 1, characterized in that said inner tube has aproximal end connected to a balloon expanding infusion port.
 5. Theballoon catheter assembly according to claim 1, wherein said inner tube,said intermediate tube and said outer tube are molded from a resinselected from the group consisting of polyethylene, polypropylene,ethylene-vinylacetate copolymer, polyester, polyvinylchloride,polyurethane, fluoric resin and polyamide.
 6. The balloon catheterassembly according to claim 1, further comprising a balloon expandingfiller made of material which assumes a liquid state when said filler isinfused into said balloon and a gelled state at a predetermined timeafter said filler has been infused into said balloon.
 7. The ballooncatheter assembly according to claim 6, wherein said filler is mixedwith an X-ray opaque substance.
 8. The balloon catheter assemblyaccording to claim 1, wherein said balloon is molded from at least onematerial selected from the group consisting of silicone rubber,polyurethane and latex.
 9. The balloon catheter assembly according toclaim 1, wherein said balloon has a circular middle portion which isthick such that said balloon takes a bottle-gourd shape when expanded.10. The balloon catheter assembly according to claim 8, wherein saidballoon includes a mesh molded from at least one material selected fromthe group consisting of nylon, polyethylene terephthalate andpolyurethane, said mesh being buried therein so as to restrict theexpansion degree of said balloon.
 11. A balloon catheter assemblycomprising:an expandable balloon having an opening in a proximal endportion, said proximal end portion having an outer peripheral surface;an inner tube having a distal portion removably inserted in said openingof said balloon; a chuck at said distal portion of said inner tube, saidchuck surrounding said distal portion of said inner tube, and said chuckhaving a plurality of holding portions extending radially outwardly atdistal ends thereof; and an outer tube coaxially surrounding said innertube with a space therebetween, said outer tube having a distal end,said chuck being adapted to be closed when said inner tube is pulled insaid outer tube by pushing said holding portions inwardly by said distalend of said outer tube to hold said proximal portion of said balloon onsaid outer peripheral surface thereof, and adapted to release saidproximal portion of said balloon when projected from said distal end ofsaid outer tube to be disengaged therefrom.
 12. The balloon catheterassembly according to claim 11, wherein:said outer tube has a proximalend connected to a check valve; and said inner tube extends outward fromsaid outer tube through said check valve, such that a body fluid isprevented from flowing reversely when said distal portion of saidcatheter is inserted in a body.
 13. The balloon catheter assemblyaccording to claim 11 further comprising an infusion portion connectedto said outer tube.
 14. The balloon catheter assembly according to claim11 ,wherein said inner tube has a proximal end connected to an infusionport for injecting into said balloon a filler for expanding saidballoon.
 15. The balloon catheter assembly according to claim 11,wherein said inner tube and said are molded from a resin selected fromthe group consisting of polyethylene, polypropylene, ethylene-vinylacetate copolymer, polyester, polyvinylchloride, fluoric resin andpolyamide.
 16. The balloon catheter assembly according to claim 11,further comprising a balloon expanding filler made of material whichassumes a liquid state when said filler is infused into said balloon anda gelled state at a predetermined time after said filler has been fusedinto said balloon.
 17. The balloon catheter assembly according to claim11, wherein said filler is mixed with an X-ray opaque substance.
 18. TheBalloon catheter assembly according to claim 11, wherein said balloon ismolded from at least one material selected from the group consisting ofsilicone rubber, polyurethane and latex.
 19. The balloon catheterassembly according to claim 11, wherein said balloon has a circularmiddle portion which is thick such that said balloon takes abottle-gourd shape when expanded.
 20. The balloon catheter assemblyaccording to claim 18, wherein said circular middle portion of saidballoon includes a mesh molded from at least one material selected fromthe group consisting of nylon, polyethylene terephthalate andpolyurethane, said mesh being buried therein so as to restrict theexpansion degree of said balloon.
 21. The balloon catheter assemblyaccording to claim 18 wherein said balloon includes a marker made ofX-ray opaque substance.
 22. The balloon catheter assembly, comprising:aballoon; a balloon catheter including a multi-tube unit comprising aninner tube, an outer tube coaxial with said inner tube, and a chuck forselectively holding and releasing said balloon, said multi-tube unithaving a distal end portion communicating with said balloon, said outertube having a distal end at which said chuck is selectively opened andclosed; and a guide sheath comprising a tube body having such an innerdiameter that said guide sheath admits said balloon catheter so as tointroduce said balloon to a required dwelling portion.
 23. The ballooncatheter assembly according to claim 22, wherein said guide sheath has aproximal end connected to a check valve.
 24. The balloon catheterassembly according to claim 23, further comprising an infusion portconnected to said check valve.
 25. The balloon catheter assemblyaccording to claim 22, wherein said guide sheath is made of materialmixed with an X-ray opaque substance.
 26. The balloon catheter assemblyaccording to claim 1, wherein said balloon includes a mesh molded fromat least one material selected from the group consisting of nylon,polyethylene terephthalate and polyurethane, said mesh being buriedtherein so as to restrict the expansion degree of said balloon.
 27. Aballoon catheter assembly, comprising:an expandable balloon having anopening in a proximal end portion thereof; an inner tube having a distalend portion which is removably inserted in said opening of said balloon;an intermediate tube coaxially surrounding said inner tube with a spacetherebetween; a chuck at a distal end of said intermediate tube, saidchuck comprising a plurality of expandable and contractible holdingportions; and an outer tube surrounding said intermediate tube with aspace therebetween; said chuck being closed when pulled into said outertube and pressed by said distal end of said outer tube to thereby holdsaid proximal end portion of said balloon, and said chuck being openedwhen pushed out of said distal end of said outer tube, to therebyreleases said proximal end portion of said balloon; and wherein saidintermediate tube and said outer tube have proximal ends connected torespective check valves; said intermediate tube extends outward fromsaid outer tube via said check valve connected to said outer tube; andsaid inner tube extends outward from said intermediate tube via saidcheck valve connected to said intermediate tube, such that a body fluidis prevented from flowing reversely when said distal portion of saidcatheter is inserted in a body.
 28. The balloon catheter assemblyaccording to claim 27, further comprising infusion ports connected tosaid check valves which are connected to said intermediate tube and saidouter tube, respectively.
 29. A balloon catheter assembly, comprising:anexpandable balloon having an opening in a proximal end portion thereof;an inner tube having a distal end portion which is removably inserted insaid opening of said balloon; an intermediate tube coaxially surroundingsaid inner tube with a space therebetween; a chuck at a distal end ofsaid intermediate tube, said chuck comprising a plurality of expandableand contractible holding portions; and an outer tube surrounding saidintermediate tube with a space therebetween; said chuck being closedwhen pulled into said outer tube and pressed by said distal end of saidouter tube to thereby hold said proximal end portion of said balloon,and said chuck being opened when pushed out of said distal end of saidouter tube, to thereby release said proximal end portion of saidballoon; and wherein said balloon has a circular middle portion which isthick such that said balloon takes a bottle-gourd shape when expanded.30. A balloon catheter assembly, comprising:an expandable balloon havingan opening in a proximal end portion thereof; an inner tube having adistal end portion which is removably inserted in said opening of saidballoon; an intermediate tube coaxially surrounding said inner tube witha space therebetween; a chuck at a distal end of said intermediate tube,said chuck comprising a plurality of expandable and contractible holdingportions; and an outer tube surrounding said intermediate tube with aspace therebetween; said chuck being closed when pulled into said outertube and pressed by said distal end of said outer tube to thereby holdsaid proximal end portion of said balloon, and said chuck being openedwhen pushed out of said distal end of said outer tube, to therebyrelease said proximal end portion of said balloon; said balloon beingmolded from at least one material selected from the group consisting ofsilicone rubber, polyurethane and latex; and said balloon including amesh molded from at least one material selected from the groupconsisting of nylon, polyethelene terephthalate and polyurethane, saidmesh being buried therein so as to restrict the expansion degree of saidballoon.